Kim, J.O. & Mueller, C.W. (1978). An introduction to factor analysis: What it
is and how to do it. Sage University Paper series on Quantitative Applications
in the Social Sciences, No 07-013. Beverly Hills, CA: Sage.

Muthén, B. & Kaplan D. (1985). A comparison of some methodologies for the
factor analysis of non-normal Likert variables. British Journal of Mathematical
and Statistical Psychology, 38, 171-189.

Muthén, B. & Kaplan D. (1992). A comparison of some methodologies for the
factor analysis of non-normal Likert variables: A note on the size of the model. British
Journal of Mathematical and Statistical Psychology, 45, 19-30.